When can a patient with ST-elevation myocardial infarction who has undergone successful primary percutaneous coronary intervention with stent implantation be discharged?

Discharge Timing After Successful Primary PCI for STEMI

Low-risk STEMI patients who have undergone successful primary PCI can be safely discharged within 48-72 hours, with emerging evidence supporting discharge as early as 24 hours in highly selected cases. 1

Risk Stratification for Discharge Timing

The decision to discharge should be based on validated risk assessment tools that identify low-risk patients suitable for early discharge:

Low-Risk Criteria (Eligible for Early Discharge at 48-72 Hours)

Patients meeting ALL of the following criteria can be discharged within 72 hours: 1

• Age <70 years 1
• Left ventricular ejection fraction >45% 1
• One- or two-vessel disease with successful PCI 1
• No persistent arrhythmias 1
• Hemodynamically stable (no vasoactive or mechanical support needed) 1
• No ongoing ischemia or recurrent chest pain 1
• Not scheduled for further revascularization 1

The Zwolle Primary PCI Index (score ≤3) or PAMI-II criteria can be used to systematically identify these low-risk patients. 1 The Zwolle score incorporates age, Killip class, post-procedural TIMI flow grade, three-vessel disease, anterior infarction, and ischemic time. 1

Very Early Discharge (24-36 Hours): Emerging Evidence

Recent studies demonstrate that discharge within 24-36 hours is safe in highly selected, very low-risk patients (representing only 2.9% of all STEMI patients undergoing primary PCI). 2, 3, 4 These patients must meet the standard low-risk criteria above AND:

• Reside within close proximity to the PCI center (typically <20 km) 3
• Have no arrhythmias observed during monitoring 1
• Demonstrate adequate ambulation tolerance 1
• Have reliable post-discharge support and follow-up arranged 1, 2

A retrospective analysis of 4,033 STEMI patients found no significant difference in 1-month (0.6%) or 6-month (1.3%) mortality between next-day discharge and standard 2-day discharge groups. 4

High-Risk Patients Requiring Extended Hospitalization

Patients with ANY of the following should NOT be discharged early and require extended monitoring: 1

• Killip class II-IV heart failure 1
• LVEF <40% 1
• Anterior wall STEMI with large territory involvement 1
• Three-vessel disease 1
• Prolonged ischemic time (>3 hours from symptom onset to reperfusion) 1
• Post-procedural complications (acute kidney injury, bleeding, vascular complications) 1
• Planned staged revascularization 1

Standard Monitoring Protocol

Initial 24-48 Hours

All STEMI patients should be monitored in a coronary care unit for a minimum of 24 hours, then transferred to a step-down monitored bed for another 24-48 hours. 1 This allows detection of:

• Arrhythmias (most common in first 48 hours post-procedure) 1
• Recurrent ischemia or reinfarction 1
• Hemodynamic instability 1
• Heart failure development 1

Pre-Discharge Requirements

Before discharge, ALL patients must have: 1, 2

• Optimized secondary prevention medications with patient education completed 1
• Confirmed cardiology follow-up within 7-14 days 1, 2
• Access to prescription medications 1
• Written action plan for chest pain or cardiac symptoms 1
• Enrollment in cardiac rehabilitation program (Class I recommendation) 1

For very early discharge protocols, remote follow-up via virtual care at 48 hours, 7 days, and 30 days, with in-person clinic visit at 4-6 weeks, has been successfully implemented. 2

Common Pitfalls to Avoid

Do not discharge early if: 1

• Limited time has prevented adequate patient education about medications and warning signs
• Secondary prevention medications have not been up-titrated appropriately
• Post-discharge follow-up is not reliably arranged
• Patient lacks social support or lives far from medical facilities
• Any clinical instability exists, even if subtle

Critical caveat: While early discharge (72 hours) is reasonable for low-risk patients, this implies limited time for proper patient education. 1 These patients should be offered early post-discharge consultations and formal rehabilitation programs to compensate for shortened hospital stay. 1

Clinical Decision Algorithm

1. At 24 hours post-PCI: Assess Zwolle score or PAMI-II criteria

   • Score ≤3 AND all low-risk criteria met → Consider discharge at 24-48 hours (if very low risk with close proximity and reliable follow-up) 1, 3, 4
   • Score >3 OR any high-risk features → Continue monitoring, plan discharge at 72+ hours 1

2. At 48-72 hours: Reassess clinical stability

   • Low-risk patients with stable course → Discharge with arranged follow-up 1
   • Any complications or instability → Extend hospitalization as needed 1

3. Beyond 72 hours: Reserved for complicated cases or high-risk patients requiring extended monitoring or staged procedures 1